Today’s Wonder of the Day was inspired by Jodi. Jodi Wonders, “How are tires recycled to make new products?” Thanks for WONDERing with us, Jodi!

When you see a cool car, what do you notice about it? In addition to the make and model, you might also remember its color and any special accessories it has. If you're like most people, though, you probably don't give much thought to the tires.

Tires are some of the most important pieces of equipment on a car. After all, they make contact with the pavement to propel you along. We usually don't pay much attention to tires, though, unless they're not performing, such as when they go flat or they slide around due to lack of traction.

There's one group of people, though, that does think about tires: environmentalists. Why? All tires wear out. In the United States, we wear out and dispose of about 300 million tires every year. Where do all those old tires go?

In the past, old tires usually went to the local landfill or were burnt. Environmentalists will tell you that neither of these solutions was good for the environment. Burning old rubber tires releases dangerous toxins and pollutes the air.

Since old tires don't biodegrade, throwing them away in a landfill simply means they'll keep stacking up over time, taking up tremendous amounts of space. They also become havens for rats and mosquitoes to breed.

Years ago, some landfills became so-called "tire mountains" due to the sheer number of old tires that had been discarded in them. Before states began to pass scrap tire laws in the 1980s, there were approximately 2-3 billion tires stockpiled in landfills.

Today, as many as 90% of those stockpiled tires have been recycled successfully. In fact, old tires have gone from an environmental nuisance to a recycling success story over the last 25 years. According to the Environmental Protection Agency (EPA), about 80% of (or roughly 240 million) scrap tires now get recycled each year.

When you buy a new set of tires today, the dealer will usually recycle your old tires for you. Of course, some people might use their old tires for a new purpose, such as turning them into a tire swing or garden planters. Alternatively, you can check with your local community recycling center for details on how and where to drop off old tires to be recycled.

When old tires get recycled, they're shipped to a commercial reprocessing plant to be treated with chemicals that break them down into material that can be reused. That material is then ground up into tiny pieces.

The EPA estimates there are currently more than 110 different products made out of material that comes from recycled tires. For example, recycled tire material is used to make rubberized asphalt, which in turn is used to resurface many roads.

Recycled tire material also finds its way into all sorts of other products, including: rubber-encased railroad ties, rubber composite decks, sports courts, running tracks, playground surfaces, public walkways, garden mulch, construction backfill, erosion control barriers, and molded automobile parts, such as engine belts and floor mats.

In some areas, old tires are burnt as an alternative fuel source to generate power. Although old tires can produce as much as 25% more energy than coal, they also produce a lot of emissions and pollutants that are not eco-friendly.

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